The invention generally relates to a hydraulically damped elastic sleeve spring and more particularly to such springs that may be used as engine supports in a motor vehicle.
A hydraulically damped elastic sleeve spring comprising an inner tube, an outer tube surrounding the inner tube with a radial spacing and a rubber spring body radially compressed in the gap formed by the radial spacing between the inner and outer tubes wherein the spring body comprises a partition forming two liquid filled chambers disposed behind each other in the direction of application of the force to be damped and connected together by at least one choke opening and wherein the partition comprises two sections that bridge the gap on both sides of the inner tube in a direction essentially transverse to the force application direction is disclosed in DE-OS No. 3343392. Such a spring may be used as an engine support for a motor vehicle and ensures, besides isolating the engine-excited high-frequency vibrations, a relatively good damping of the low-frequency vibrations caused as the motor vehicle travels over unevenesses in the road. These low-frequency vibrations can lead to, in the worst case, increased-amplitude vibrations of the engine.
Independently of the magnitude of the amplitude of such vibrations, the forces released in this process act predominantly in the vertical direction. This is taken into consideration in the sleeve spring disclosed in DE-OS No. 3343392 by the fact that in the vertical direction, a damping device and end stops for limiting the vibration amplitude are provided. On the other hand, neither a damping device nor an end stop are provided for vibrations occurring transverse to the vertical force application direction. This may result in relatively large displacements of the engine in the transverse direction, especially when the vehicle is negotiating curves.
The invention is directed to the problem of providing a elastic sleeve spring that can better suppress transverse vibrations, yet still be of a simple design and have spring and damping properties in the vertical direction that are at least as good as those attainable with the rubber sleeve spring disclosed in the above-mentioned German patent publication.